This invention relates to a recording character configuration changing system for changing a configuration of a recording character, which is adaptable for an electrophotographic recording system with an optical fiber tube.
One of the various electrophotographic recording systems successfully developed and put into practice in recent years is provided with an optical fiber tube (OFT) as an exposure device. In this recording system, the OFT effects line-scanning on the surface of the photosensitive drum to form an electrostatic latent image on the photosensitive drum. The latent image is developed by toner to be visualized and then the visualized image is transferred onto a recording paper and then is fixed to finally form a picture of information on the recording paper. In this type electrophotographic recording system, all the dot signals on the top row of a dot array representing each of those characters recorded on the first line of a recording paper are applied serially to the cathode of the OFT as video signals in the first scanning. In the second scanning, all the dot signals on the second row of the dot array are applied to the same as the video signals, similarly. The scanning is repeated for all the rows of one character dot array derived from the character signal generator. In this way, the characters on the first line on the recording paper are recorded.
Let us consider now a magnification of the recording character as an application of the recording system mentioned above. In this case, it is assumed that a time interval between the start of one scanning and the next scanning is fixed and that an exposure speed of an electron beam relative to photosensitive drum is uniform. For magnifying a character of a (vertical) by b (horizontal) into an enlarged character of 2a by 2b, a time interval between the starts of one dot recording and another dot recording is doubled for doubling the horizontal size of the character. This is realized by making half the frequency of a shift pulse applied to a shift register for shifting serial dot signals converted to be applied to the cathod of the OFT. Further, the number of scannings per one row of the dot array of each character when the characters are recorded, is also doubled. The scanning time for recording a character with a basic size is assumed to be one, for example. For recording a magnified or enlarged character with the horizontal size 2a, the scanning time is doubled for one line of each character. As mentioned above, in order to magnify the basic size character to a character of 2a by 2b, the frequency of the shift pulse is reduced half and the scanning of the same video signal is continuously repeated two times. A similar operation is applied for the magnifications of 3a.times.3b, 4a.times.4b, 5a.times.5b.
In the above-mentioned system, the magnification of the character is performed stepwise and not continuously. Practically, however, one often encounters a case needing characters with intermediate size between the adjacent sizes of the characters magnified by the above-mentioned system.